The disclosure of Japanese Patent Application No. HEI 11-23033 filed on Apr. 28, 1999, including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the invention
The present invention relates to a temperature regulator for a fuel cell and, more particularly, to a temperature regulator capable of regulating a temperature of a fuel cell and utilizing heat of the fuel cell.
2. Description of the Related Art
According to what is proposed in the related art of a temperature regulator for a fuel cell of the aforementioned type, a cooling system for the fuel cell is equipped with a heating device utilizing heat of the fuel cell and with a burner for heating a heat exchange medium in the cooling system (as disclosed, for example, in Japanese Patent Application Laid-Open No. HEI 6-260196).
This regulator has a circulation circuit through which the heat exchange medium respectively circulates through the fuel cell, the heating device and the burner. When the fuel cell is in normal operation, the heat generated by the fuel cell can be used to carry out heating. Also, when starting the fuel cell, this regulator can heat up the fuel cell by heating the heat exchange medium through the burner.
However, this regulator has a problem in that the heating device may not be able to produce a sufficient heating effect even if the fuel cell has been started and has become operable. The heat exchange medium heated by the burner is first sent to the fuel cell. Therefore, if the fuel cell is operable but not in normal operation, the amount of heat supplied to the heating device is insufficient. Also, this regulator has a problem in that the heating device is unable to function sufficiently when the amount of heat required for the heating device is greater than the amount of heat generated by the fuel cell. The burner may then be used to heat the heat exchange medium for the purpose of generating a required amount of heat. However, if the fuel cell is in normal operation, the heat exchange medium cannot be heated because of the necessity to cool the fuel cell.
It is an object of the temperature regulator for the fuel cell according to the present invention to rapidly heat up the fuel cell during the starting operation.
It is another object of the temperature regulator for the fuel cell according to the present invention to confine a temperature of the fuel cell during operation to a suitable operational temperature range.
It is yet another object of the temperature regulator for the fuel cell according to the present invention to effectively utilize the heat generated by the fuel cell.
It is yet another object of the temperature regulator for the fuel cell according to the present invention to remedy a deficiency in heat when effectively utilizing the heat generated by the fuel cell.
In order to achieve the above and other objects, according to a first aspect of the present invention, there is provided a temperature regulator for regulating a temperature of a fuel cell, including a circulation circuit through which a heat exchange medium exchanging heat with the fuel cell circulates, a medium circulator for circulating the heat exchange medium through the circulation circuit either in a normal direction or in a reverse direction, a cooler provided in the circulation circuit to cool the heat exchange medium, a cooling bypass device for switching the circulation circuit such that the heat exchange medium bypasses the cooler, a heat utilizer provided in the circulation circuit to carry out work utilizing heat of the heat exchange medium, a heat utilizing bypass device for switching the circulation circuit such that the heat exchange medium bypasses the heat utilizer, and a heater provided adjacent to the fuel cell in the circulation circuit and capable of heating the heat exchange medium.
In the temperature regulator for the fuel cell according to the first aspect of the present invention, the cooling bypass device can either incorporate the cooler into the circulation circuit or bypass the cooler, and the heat utilizing bypass device can either incorporate the heat utilizer into the circulation circuit or bypass the heat utilizer. Consequently, it is possible to regulate a temperature of the fuel cell and utilize the heat of the fuel cell. Also, since the heat exchange medium can be heated, it is possible to heat up the fuel cell or supplement an amount of heat required for the heat utilizer.
The temperature regulator for the fuel cell of the present invention may include a state detector for detecting a state of the fuel cell, and a controller designed to control the medium circulator, the cooling bypass device, the heat utilizing bypass device and the heater, based on the state detected by the state detector. In this construction, the fuel cell can be maintained in a desired state.
In the temperature regulator for the fuel cell according to the aspect of the present invention wherein the state detector and the controller are provided, the controller may be designed to control the cooling bypass device and the heat utilizing bypass device such that the circulation circuit bypasses the cooler and the heat utilizer when the state detector detects a starting state of the fuel cell, and the controller may be designed to control the heater such that the heat exchange medium is heated, and to control the medium circulator such that the heat exchange medium circulates through the circulation circuit according to the respective order of the heater and the fuel cell. In this construction, the fuel cell can be heated up rapidly.
Further, in the temperature regulator for the fuel cell according to the first aspect of the present invention wherein the state detector and the controller are provided, the controller may be designed to control the cooling bypass device and the heat utilizing bypass device so as to incorporate the cooler and/or the heat utilizer into the circulation circuit when the state detector detects an operable state of the fuel cell, and the controller may be designed to control the medium circulator such that the heat exchange medium circulates through the circulation circuit according to the respective order of the fuel cell, the heater and the cooler and/or the heat utilizer. In this construction, the fuel cell can be cooled, and it is possible to supplement heat if the amount of heat required for the heat utilizer is deficient. In the temperature regulator for the fuel cell according to this aspect of the present invention, the state detector may be provided with a temperature detector for detecting a temperature of the fuel cell, and the controller may be designed to control the medium circulator, the cooling bypass device, the heat utilizing bypass device and the heater such that the temperature detected by the temperature detector is confined to a predetermined temperature range. In this construction, the fuel cell can be operated within a predetermined temperature range.
In the temperature regulator for the fuel cell according to the aspect of the present invention wherein the fuel cell is operated within the predetermined temperature range, a heat utilizing state detector for detecting a state of the heat utilizer may be provided, and the controller may be designed to control the cooling bypass device, the heat utilizing bypass device and the heater, based on the state of the heat utilizer detected by the heat utilizing state detector. In this construction, the heat utilizer can be maintained in a desired state.
In the temperature regulator for the fuel cell according to the aspect of the present invention wherein the heat utilizing state detector is provided, the controller may be designed to control the heat utilizing bypass device so as to incorporate the heat utilizer into the circulation circuit when the heat utilizing state detector detects a state where the heat utilizer utilizes heat. In this construction, the heat utilizer can utilize heat effectively.
In the temperature regulator for the fuel cell according to the aspect of the present invention wherein the heat utilizer is incorporated into the circulation circuit, the heat utilizer may be provided with an information detector for detecting information on any excess and deficiency of a required amount of heat, and the controller may be designed to control the heater and the cooling bypass device based on the information detected by the information detector. In this construction, the heat utilizer can function adequately.
In the temperature regulator for the fuel cell according to the aspect of the present invention wherein the heat utilizer is provided with the information detector, the controller may be designed to control the heater such that the heat exchange medium is heated when the information detector detects information on a deficiency of the required amount of heat. In this construction, it is possible to supplement a required amount of heat.
Further, in the temperature regulator for the fuel cell according to the aspect of the present invention wherein the heat utilizer is provided with the information detector, the controller may be designed to control the heater such that the heat exchange medium is not heated when the information detector detects information on an excess of the required amount of heat. In this construction, it is possible to prevent the supply of an excessive amount of heat. In the temperature regulator according to this aspect of the present invention, the controller may be designed to control the cooling bypass device so as to incorporate the cooler into the circulation circuit when the information detector detects information on an excess of the required amount of heat, although the heater is controlled so as not to heat the heat exchange medium. In this construction, the heat utilizer can suitably utilize heat. Furthermore, in the temperature regulator according to this aspect of the present invention, the controller may be designed to control the cooling bypass device such that the circulation circuit bypasses the cooler prior to the heating of the heat exchange medium by the heater when the information detector detects information on a deficiency of the required amount of heat with the cooling bypass device being so controlled as to incorporate the cooler into the circulation circuit. In this construction, it is possible to utilize heat efficiently.
In the temperature regulator for the fuel cell of the present invention, the heat utilizer may be a heating device that carries out heating by exchanging heat with the heat exchange medium.